It would be nice to see a chart showing the current breakdown of active Firefox installations by OS, on the big boards in the office. Knowing the numbers, especially for the less popular OSes, may help us prioritize our own goals. At the very least, will be interesting.
There are a lot of ways to count these numbers, and a lot of caveats that make them actually quite a bit wrong (under-reporting Linux being a topic of active development). Can you expand a bit on why/how knowing something more than "Oh, basically all of them are Windows and then there's a tiny bit that's about equally Mac and Linux" would be helpful?
Yes, this bug was born by my suffering many black-screen events in Firefox on Windows. It woudl happen multiple times a day, but never predictably enough for me to make a test case. The problem seems to have passed for me, but here are others: https://bugzilla.mozilla.org/show_bug.cgi?id=1163440 https://bugzilla.mozilla.org/show_bug.cgi?id=1347664 https://bugzilla.mozilla.org/show_bug.cgi?id=1339717 https://bugzilla.mozilla.org/show_bug.cgi?id=1348528 I would like us to focus more on Windows testing and dogfooding, but we work in a Linux/Mac bubble. In this bubble, people act as if Windows users make up less than 10% of Firefox users. Convincing people to improve our testing on Windows is hard when their daily office experience is the opposite. Any reasonable definition of "Windows user" will be better than nothing.
Does the Firefox Hardware Report help? https://metrics.mozilla.com/firefox-hardware-report/#goto-os-and-architecture
The stacked, horizontal, bars at the top are quite good . Having the names of the Operating systems show (even when not hovering) would be best  https://metrics.mozilla.com/firefox-hardware-report/
It looks like SQL.tmo is the better place to look for this information with the client_count dataset instead of the telemetry.mozilla.org aggregates: https://sql.telemetry.mozilla.org/dashboard/client-count-os